Development devices that include a development roller having surface unevenness are known. For example, JP-2007-178901-A and JP-2007-121951-A propose forming projections having a substantially identical height and recesses having a substantially identical depth regularly in the surface of the development roller and disposing rubber developer regulators (i.e., doctor blades) are disposed in contact with the development roller to adjust the amount of toner carried thereon.
Such configurations are advantageous in that toner present on the projections can be removed by the developer regulator and that the amount of toner carried on the development roller can be constant because only toner present inside the recesses can be carried thereon. The amount of toner carried to a development range can be set to a desired amount by designing the recesses to have a desired capacity to contain toner.
Additionally, providing a supply roller at a position facing the development roller is proposed. Toner contained in a toner containing chamber provided inside the development device is supplied by the supply roller to the development roller in a supply nip where the supply roller faces the development roller. As the development roller rotates, toner supplied thereto passes through the development range, returns to the supply nip, and then is collected by the supply roller. The supply roller and the development roller may rotate in an identical direction in the supply nip.